Morphologische Entwicklung von Pt (111) bei Pt-Deposition und Ionenstrahlerosion

Kalff, M.

Dissertation / PhD Thesis/Book

Morphologische Entwicklung von Pt (111) bei Pt-Deposition und Ionenstrahlerosion

Kalff, M. (Corresponding author)FZJ*

1999
Forschungszentrum, Zentralbibliothek Jülich

Jülich : Forschungszentrum, Zentralbibliothek, Berichte des Forschungszentrums Jülich 3625, (1999) = Bonn, Univ., Diss., 1999

Please use a persistent id in citations: http://hdl.handle.net/2128/20368

Report No.: Juel-3625

Abstract: The homoepitaxy and the Xe+ ion beam erosion of Pt(111) were investigated with a scanning tunneling microscope (ST Ivl) . Besides the high resolution of the S T ivl the very low Base pressure was fundamental for the investigations. The experiments concerning homoepitaxy of Pt can be devided in three parts . The first part deals with films with a thickness of less than 5 monolayers deposited under very clean conditions (Ptot < 2 . 10-11 mbar, Pro 5 . 10-12 mbar) . Island densities and shapes as WeYl1l as the growth mod.]ee were investigatecdu in the temperature ranuge.. between 200 1K and 600 K. The results are compared to previous measurements . The effective step barrier estimated at 400 K appears to depend strongly on the island shape. The very clean deposition conditions were obtained by using a new designed evaporator consisting of a Pt wire heated resistively . The construction allows the heating of the Pt wire, while keeping most of the other components close to room temperature . The absente of the usually used electron beam prevents the formation of ions and thus the increase of the background CO-pressure. A second group of experiments deals with the influence of minute amounts of CO on Pt(111) homoepitaxy. The main differente between Pt islands grown on Pt(111) in the temperature range 350 K - 450 K with and without additional CO resides in the nature of the steps bordering the islands . The change from A to B steps occures at CO coverages of a few thousandths of a monolayer . Also the other aspects of the growth process like island density and step edge barrier are infiuenced by minute amounts of CO. In the third part of the growth experiments the evolution of growing Pt films at 440 K is investigated . Of special interest are the mound separation and the surface roughness . Their evolution from the submonolayer regime up to 300 deposited monolayers was monitored

Note: Record converted from VDB: 12.11.2012
Note: Bonn, Univ., Diss., 1999

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